The overall objective of this project is to study defense mechanisms of the trachebronchial tree against particulate matter and bacterial and viral pathogens, and to determine how alterations of these mechanisms may contribute to the genesis and chronicity of chronic bronchitis and emphysema. In the present year we are working on 1) the improvement and modification of methods of studying deposition and clearance in order to develop a test which could be widely used, 2) the development of methods for detailed regional quantification of deposition and clearance of particles in the lungs; for this purpose we are designing programs for computer analysis of data obtained with a scintillation camera, 3) the determination of it, and when, there is a regeneration of mucociliary activity after cessation of smoking and after recuperation from respiratory virus infection, 4) the effect on mucociliary clearance of viruses which are usually associated with upper airway disease, such as Rhinovirus, 5) the chemical composition of sputum obtained from patients with chronic bronchitis, with special emphasis on the bonding of glycoproteins in this sputum in an attempt to correlate biochemical findings with clearance data.